Manhole, sewer, or other conduit and method of constructing the same.



C. H. FROST.

MANHOLE, SEWER, OR OTHER CONDUIT, AND METHOD OF CONSTRUUING THE SAME.

APPLICATION man NOV. 12. 1914.

1,144,46 Patented June 29, 1915.

lNl/E/VTOR UFFMEO OHARLES, H. FROST, 0F PASADENA, CALIFORNIA.

MANHOLE, SEWER, OR OTHER CONDUIT AND METHOD OI CONSTBUGTING THE SAME.

Specification of Letters Patent.

Patented June 29,1915.

Application filed November 12, 1914. Serial No. 871,683.

To'all whom it may concern Be it known that 1, CHARLES H. l nos'r, acitizen of the United States, residing at Pasadena, in the county ofAngeles and State of California, have invented certain new and usefulImprovements in Manholes, Sewers, or other Conduits and Methods ofConstructing the Same, of which the followin is a specification.

his invention relates to methods of building man holes, sewers, or othercondu ts.

In my co-pending application Semal No. 863,426, filed September 25,1914:, I have described and claimed an improved form of brick taperingor wedge-shaped'in cross-sec tion and havinga longitudinal r1b ononeside and a longitudinal groove upon the other side, whereby when thebricks are laid s1de by side in mortar to form a circular sewer or manhole they will interlock one with the other, and be held rigidlytogether against the strains to which they are subjected, arising fromthe weight of the bricks, and the pressure of the surrounding earth.

In building a man hole it is the usual practice to start at the bottomwith a circular course of bricks and build up the structure for, say,about four feet in helght for a given diameter, as for example four feetin diameter. Thence the man hole is built up of gradually diminishingdiameters, taporing up to two or three feet at the top, the depth ofthese man holes varying 1n difierent locations, according to the toography of the ground. Man holes which ave been heretofore constructedin this manner, of

common solid building brick, required two rings of such bricks to everycourse, in order to be sufliciently rigid to withstand the strainsagainst the walls of the man holes, whereas with hollow interlockingbricks of the character disclosed in my prior application above referredto, sufficient rigidity of the walls has been effected by using a singlerow or ring of bricks at each course. This results in an enormous savingin the number of bricks required to build a man hole with the brick ofmy said a plication as compared with the number 0 common bricks whichwere required under former practices. In building the tapering portionsof these man holes, where the diameter is progressively diminished asthe height increases, 1 have discovered that tapering bricks having thestandard measurements at its two side edges (as for instance 3 inches atits widest edge and 2% inches at its narrowest edge) are unsuited, ifused alone, for

building a progressively tapering man hole; but by introducing therewitha suitable number of preformed tapering bricks, known as filler bricks,whose inner or narrowest edges are less in width, compared with theWidth of their outer or wider edges, than the standard brick of thedimensions above-referred to, a man hole of gradually decreasingdiameter may be built up. The number of these filler bricks that areintroduced in the successive courses, in proportion to the standardbricks, will depend upon the diameter of the man hole, and theproportionate number will be gradually increased as the man holedecreases in diameter. In practice it is found that bricks having thestandard measurements, or the lesser degree of taper from their wider totheir narrower edge, as above referred to may be used exclusively tobuild up the cylindrical portion of the man hole, for a distance of 4feet, for instance, to the point where the man hole begins to taper.From this point upward to the smallest diameter the filler bricks willbe introduced in increasing numbers at each course, and at the point ofsmallest diameter, which may be 2 feet, there will be employed an equalnumber of standard, and filler bricks, arranged alternately, one withthe other, in the final circular course of the man hole.

The mode of constructing a ta ering condui in the manner above speci ed,whereby gradually diminishing or tapering structure is produced by usingbricks which have been previously made of two degrees of taper,constitutes the important feature of my method.

Another important feature of the invention comprises a filler brick,wedge-shaped or tapering in cross-section, and provided in one side withan enlarged groove, and On its other side with a relatively diminishedrib which tapers from its base outwardly, the angles of union of thewalls of said groove and rib with the side walls of the rick presentingcurves instead of sharp angles. The advantage of thus forming the ribsand grooves is that the rib has additional strength by reason of itswidened base, and by making the groove sufliciently larger than the rib,opportunity is presented for swelling of the rib when the brick isreleased from the die, and also for the groove of the ribs and grooves wen the bricksare' laid side by side to form a man hole.

These, and other important features of the invention will be morepartiou lar ly described and claimed.

In the drawings: Figure .1 represent's a.

vertical sectional view of. a man hole which has been constructed in.accordance with the present invention; Fig. 2 is an enlarged sectionalplan view, on the line 2-2, Fi 1, showing a portion of a circular course0 the two kinds of bricks, laid in accordance with this method; Fig. 3is a transverse section of the standard brick,-and Fig. 4 isa-transverse section of the filler-brick.

The man hole illustrated in Fig. 1 comprises a cylindrical portion 2,WhlCh, as is usual in such structures, is built up of sum cessivecourses to the desired height, and thereafter the courses of bricks areprogressively reduced in diameter as the man hole tapers from thecylindrical portion upward to the top course of bricks which is locatedat or near the surface of the ground. In building such a man hole undermy invention I preferably use for the cylindrical part 2, my tapering,interlocking brick as described in my co-pending application abovereferred to. These bricks may be 3 inches at their widest edge, andtaper slightly to their narrow edge, which may be 2% inches wide. Thebricks are provided upon one side with a longitudinal rib, and upon theopposite side with a longitudinal groove which is larger than the rib inorder to allow for the necessary amount of mortar between the edges ofthe bricks, and in the grooves surrounding the ribs, so that when thebricks are laid side by side to form the circular courses the ribs andgrooves will interlock, and hold the bricks rigidly together, andprevent relative sliding movement of the bricks in the planes of theiradjoining faces. After a suitable number of courses have been laid, ofuniform diam-' gradually diminishing taper in the circular walls of theman hole. At this chat in the construction I, therefore, intro uce asuitable number of the filler bricks 3 one of which is shown in plan inFig. 4. These bricks are formed tapering, from their widest edge totheir narrowest edge, but such taper is increased as compared with thetaper of the standard brick, and for practical purposes I have foundthat a filler brick, whose widest edge, ab is 3;} inches,

should-at its narrowest edge c-0Z, be approximately 1% inches. Thegroove 6 in the side wall o this brick is, as shown, eased ,ofi or,rounded so as to present smooth curves whereits wall joins the side ofthe brick, and the rib 8 on the opposite side is similarly eased off orcurved where its sides join the side wall of the brick, so as tomerge'into the latter. The base of this rib is also made thicker thanits outer end portion, so that the rib is wedge-shaped, and this hasbeen found to increase the strength of the rib. When these bricks arereleased from the die in which they are formed there is a tendency forthe ribs 8 to swell and increase in size, and it is also a fact that thegrooves 6 are frequently diminished in size by the pressure exerted onthe bricks when they are stacked in the kiln. For these reasons it isimportant that the grooves should be of substantially larger size thanthe ribs, and by thickening the base of the ribs strength is added, andthe danger of ribs being distorted or sheared off is materially reduced.These bricks are provided with openings 10, 12, for the purposes ofrendering the bricks lighter, and freely admitting the heat to theinterior of the bricks while they are being burned with a view to havingthe burning operation equalized throughout the brick, all as set forthin my co-pending application. In the filler brick herein described thesize of these openings has been reduced somewhat, and as the end c-(Z ofthe filler bricks is so narrow it has been found expedient to form thehole 10 near this end of the brick of circular form, as this gives thebest results.

In building a manhole of the type shown in Fig. l, the cylindricalportion is first formed by laying a suitable number of circular coursesof bricks, all of the standard size and having the same degree of taper,with each circular course of the same diameter, until the desired heightis reached. From this point upward the courses of progressivelydecreasing diameters are laid to make the tapering portion of themanhole. On the top course of the section 2, a mortar joint 13,wedge-shaped in cross-section, having its thickest part at the outerside of the manhole and tapering to a fine edge at able number of thefiller bricks, or those of the greater degree of taper, and the diam-Licence eter of each, successive circular course is diminished, byincreasing the number of the filler bricks that are used in proportionto the number of the standard pricks until the smallest diameter desiredis reached. In the final course it has been found that the filler bricksmay be used in; equal number with the standard bricks, and the two kindsof bricks are placed alternately, first one and then the other,throughout the course. The inclination of the base 13, which causes thebricks to tilt inwardly, together with the progressive and regulardecrease in the size of each successive circular course of bricksresults in the production of a structure having a smoothly tapered andan even and regular outer surface. By referring to Fig. 2, which shows aportion of one course of bricks used in the production of the taperingsection 4, the diiference in taper between the standard bricks 1 and thefiller bricks 3, will be readily seen. The dotted lines which areprojected as extensions of the sides of the standard bricks form seetorsof a larger circle than the circle of which the sectors formed byextending the sides of the filler bricks form parts.

While I have, throughout this specification, referred to the brickshaving the lesser degree of taper, from end to end, as the standardbricks, and to the bricks having the greater degree of taper, from endto end, as the filler bricks, it is to be understood that both of thesebricks are standard in a sense, that is, each brick is pre-formed, andis produced in great quantities with its desired degree of taper,although the so-called filler bricks are formed with the decidedlyincreased amount of difference between the length of inner and outeredges, as compared with the standard brick. In order to distinguishthese two kinds of bricks from each other, however, I shall, in theclaims, employ the terms standard and filler in the senses hereinexplained.

While I have described my invention as relating to certain improvementsin man holes and methods of constructing the same, it is to beunderstood that the invention is not necessarily limited to man holes,but the method of construction and the elements heretofore described maybe employed, if

desired, in sewers, or other conduits of circular cross-section.

Having thus described my invention what I claim and desire to secure byLetters Patent of the United States is:

1. That improvement in methods of producing a tapering man hole,conduit, or similar structure, which comprises providing a suitable:number of pre-formed standard bricks having a given'taper from theirinner to their outer edges, and a suitable number of pre-formed fillerbricks, having a greater degree of taper, laying successive courses ofdecreasing diameters by using a suitable number of said standard bricks,with a number of said filler bricks at spaced intervals in each course,and increasing the number of filler bricks in proportion to the numberof standard bricks used as the diameter of the structure decreases.

2. That improvement in methods of producing a tapering man hole orsimilar structure, which comprises providing a number of pre-formedstandard bricks having a given taper from inner to outer edges, and anumber of pre-formed filler bricks having a greater degree of taper,laying a suitable number of said standard bricks side by side with asuitable number of filler bricks to form a circular course, andcontinuing the structure by adding successive courses of decreasingdiameters, each added course containing a greater proportionate numberof the filler bricks, until the course of smallest diameter is laid tocomplete the structure.

In testimony whereof I aflix my signature in presence of two witnesses.

CHARLES H. FROST.

Witnesses:

HOWARD FRos'r, H. B. POTTER.

